1. Please disable "can be sold"

2. You can block the product

Hello,

If its for a specific user group, you could add constraint and raise a validation or user error like in the below code:

class SaleOrderLine(models.Model):

    _inherit = 'sale.order.line'

    @api.constrains('product_id')

    def _check_product_id(self):

        for line in self:

            if line.env.user.has_group('base.group_user'):

                raise exceptions.UserError("You are not allowed to add products to sale orders.")

Here if the user belongs to the group 'base.group_user', that user will get a popup and will not be able to add products in the order line.

Hope it helps.